This work has caused me a great deal of anguish. Over the years I have tried to consider the global challenges that have been rapidly emerging in our time. My considerations are from a systems perspective — I seek to understand how everything is connected and influences every other thing.

Invariably I keep coming back to two factors which seem to lay at the heart of the matter. The first is the fact of biophysical growth in a finite world, specifically the human population and our propensity to consume more resources per individual over time.

The second is actually even more so at the root of the first. That is the stunting of the one capacity that we humans evolved that could have made us able to transcend our ordinary biology (causes of the first issue) and learn to live in balance with nature. The capacity I refer to is sapience (below). Human evolution produced a nascent capacity for making good, wide-scaling judgments in complex, especially social, domains — that is our sapience.

Unfortunately, today, I think the evidence suggests that that capacity never developed further. Indeed, it seems that it is now almost vestigial, like the little toe or the appendix. Today, the average human being is not very good at making sound judgments of high moral quality. In any case, when you take into account all of the various contributing factors, biological, physical, sociological, psychological, etc. it appears that we have gotten ourselves into a terrible predicament. After spending years thinking about, and searching for solutions that are acceptable in light of all of those factors, I'm afraid I come up empty handed.

What I have written below gives absolutely no pleasure whatever. I am not a doomer or a survivalist. I do not hate humanity and want to see the end. I have children and friends whom I would love to see have happy lives. But what I hope I am, if nothing else, is intellectually honest. If my work has brought me to this point I cannot go on writing as if these conclusions didn't exist.

Population

For several years now I have been writing a contribution to the Global Population Speak Out (GPSO). See: “The Hardest Moral Dilemma of All”. A larger number of people have been writing profusely about the subject of overpopulation and the consequences. And nothing has happened. This is not because these many people have not had worthwhile things to say, suggestions about what might be done, but because the messages fall on deaf ears. The majority of people in this world are either not able to hear the message or they are hostile, for ideological reasons, to the implications of the claims for overpopulation.

I have been thinking about this for several years and have been building the arguments for why what I am about to say is actually the only real solution that could result in the survival of enough representatives of Homo sapiens to ensure that the genus is still around one million years from now. No one is going to like this. I suspect that many people in the anti-growth community are not going to like what I have to say, thinking, perhaps, that my message will damage their own credibility. Believe me when I tell you that I don't like it. But my feeling is that it needs to be said. Even while there are a growing number of people in the world who have gotten the messages and are now aware of the problems, there simply aren't enough, nor do they actually understand the full implications of what is happening.

All I ask is that you not sacrifice the messenger!

The Problem — We Are in Overshoot

Is there any doubt that this statement is true? The world stands on the brink of a human population of seven billion people. Way too many of the current population are living in abject poverty and too many are underfed if not outright starving. Water supplies are in jeopardy, both for drinking and for agriculture. Documented extinction rates are going up due to the human footprint destroying habitat for other species. The climate is already showing severe instability and the worst case models suggest that things are going to get much worse. Sea levels are rising and the threat is that those levels are going to be high enough to threaten a huge fraction of the world's population that live in coastal areas. Finite resources, especially fossil fuels, have been depleted to the point that the cost of extraction of the next unit of the resource has reached diminishing returns. See my take on overpopulation and its implications in my book review of William Catton's, Bottleneck, “Humanity's impending impasse”.

In systems ecological terms the human population shows (empirically) all the signs of being in overshoot. The population is simply too large for the long-term carrying capacity of the planet. We have gotten here through two basic factors. The first is the incredible inventiveness of the human mind and the technologies that have allowed humans to colonize almost the whole planet, “conquer nature”, and escape the ordinary biological selection mechanisms, like diseases and genetic defects. The second is the most amazing bequeath of nature in the form of incredibly energy-dense fossil fuels (actually fossil sunshine) that have allowed the human population to substitute machine work for human labor, at least in the developing areas of the world. The industrial revolution was largely about the interactions of these two factors permitting growth of the population and growth of the per capita consumption of resources in those sub-populations that got lucky. Energy and technology go hand in hand in accounting for the major trajectories of history. Human ingenuity certainly played a role, but, if we are honest with ourselves, that role is more as discovery and exploitation (for hedonic reasons) rather than intentional invention. We were just lucky recipients of the laws of nature when the energy bank account was full. Now that the bank is running dry and we may have reached the limits of invention, things have changed completely. We are in the Wiley Coyote moment (when he runs off the cliff and realizes that he has no support). We have no way to keep the overshot population supported as is.

This essay addresses a simple but profound observation. There is no feasible solution to the problem of population overshoot if stated thusly:

"We need to find a way to reduce the population to a level that is sustainable in the long run and minimally impactful (in the negative sense) on the environment. And we want it to be accomplished in a humane manner. And, oh yes, we want everyone in the population to live the good life (no sacrifices); we want “sustainable economic growth”!

Put this way, many people think of humane population reduction as some relatively non-coercive process where, perhaps, suddenly everybody gets it, including those of the various religious faiths that now preach being fruitful, and practices contraception. Problem solved. This vision maintains that if a substantial proportion of the Earth's population practices family planning then the above result will follow. Then the sub-problem simply becomes one of convincing everyone to practice family planning.

Even aside from the infeasibility of getting everyone to agree that family planning is a good thing to do, I claim that the gradual reduction in the population that could conceivably result would still not be a solution to the problem. As I will argue later, the rate of decline simply would not be great enough. We are facing a complete population crash simply due to the fact that we have entered an energy decline phase that humanity has never faced before in its entire history, at least not on a global scale. This claim pivots on the notion of what constitutes a ‘feasible’ solution to a specified problem.

Feasible Solution Space

A problem is said to have a feasible solution when there exists a volume in a multi-dimensional parameter space where all of the requirements are met and all of the constraints are satisfied and the objective is fulfilled. When constraints are tight or requirements are narrow that volume might be very small. Or, alternatively, if the constraints are loose or the requirements wide the volume might be quite large. Moreover, there may be many pathways by which the requirements might be met while not violating any constraints. Such problems are well defined and are at least soluble in principle.

Figure 1. A feasible solution exists in the problem space when there is some region (volume) in which all requirements can be met while not violating any constraints. Abstractly, the constraints and requirements (appropriately scaled) can be mapped onto a problem space to see if there is any such region where all of these intersect.

Many more kinds of problems, especially complex social problems where inherent conflicts permeate the problem space, cannot be solved, even in principle. As shown in Fig. 2, if even one requirement cannot be found to map in overlap with other requirements, then no feasible region exists and nothing can be done to solve the problem other than to ignore the requirement(s). But then you have just solved a different problem, by definition.

Figure 2. If only one requirement does not map to overlap with the others then no feasible solution exists for the problem as defined.

Even more generally, not all constraints and requirements are actually specified so that one cannot know if a feasible solution might exist or not. Figure 3 depicts a more ordinary sort of social problem (or what is known as a ‘Wicked Problem’.

Figure 3. The worst-case situation for problem definition is when the problem is "wicked". The problem is under specified in that not all constraints and requirements are actually known when trying to find a solution volume. Poorly defined problems such as the overpopulation problem easily fall into this category. They are unsolvable in principle and practice.

In real life social problems it is almost always the case that not all the requirements or constraints can even be specified let alone matched up in such a way as to provide a solution. What more typically happens in cases where some kind of “solution” seems to have been found, is that some hidden constraints or misunderstood requirements are simply not specified (as in Fig. 3). Implementation of the solution then either runs into the formerly hidden difficulty, or may be completed but the solution ends up creating more problems. The infamous unintended consequences of supposed solutions is more often the rule than the exception.

Overpopulation is, arguably, the most difficult and under specified social problem of all. Difficult for the obvious reasons that the vast majority of people in this world are compelled by biology to procreate, think it is their god-given right to do so, and mostly don't realize what the global consequences are.

It is under specified in the sense that we really don't know all of the factors that shape the population growth rate. For example, not very long ago, population scientists (mostly social scientists with some help of biologists) were proclaiming that the problem would solve itself owing to the demographic transition, the observation that as countries became wealthier (more developed) the fertility rate declined (as in the average number of babies per child-bearing aged woman).

In theory, the global population size would top out at say nine billion people and then even start to decline. Everyone could breathe a sigh of relief and go on with BAU. The UN wants to push ahead with the Millennium Development Goals so as to enrich every nation and thereby (through the demographic transition) stabilize the population. In other words, they think making everyone richer will solve the problem. What they have not accounted for, of course, is that making everyone richer means consuming even more resources! And, actually some scientists and governments (whose tax bases are associated with the number of people in the work force) have started worrying about the opposite problem — too few people — as it would affect the economics of the country.

Now comes new evidence that suggests the demographic transition is not a one-way phenomenon. Rather after reaching a certain level of development fertility rates stop declining and even start climbing again. The jury is still out on this but there are other reasons to believe that faith in the demographic transition phenomenon is a poor strategy for solving the problem of overshoot. But the point is that we just do not know all there is to know about population dynamics to take any comfort in an observation like this.

For one thing, even if the transition phenomenon were shown to be effective after all, it still relies on the economic development of the poorer nations where, it turns out, the fertility rate is still high. In a perfect world where there is unlimited energy and the wastes we humans produce would magically disappear that might be fine. But we don't live in that world.

We live in a world where the energy needed to produce wealth is peaking and going into its own transition downward (see below). We live in a world in which the garbage and pollutants we produce in living the good life are accumulating at a rate much faster than nature can handle. Global warming due to accumulations of CO2 in the atmosphere and ocean acidification due to its accumulation in the oceans are two instances of unintended consequences of us clever humans solving the problem of how to live the good life and avoid the nastier forms of natural selection. And here is the point: The rate of the bad consequences developing into catastrophes is much greater than the rate of demographic transition. Indeed, without the energy supplies to drive that transition, it won't happen at all in what would have been the developing world.

Nature alone holds the secrets of the population problem in terms of establishing the biophysical constraints and the biological requirements. Natural systems have been pursuing the feasible solution spaces since life began on the planet. I say pursuing because any change (say a mutation) in one part of the system invariably leads to changes in other parts and changes in the original constraints/requirements sets. That is what drives evolution.

In fact, I claim evolution is the only feasible way to find a solution to the overpopulation problem. That is what I will outline below. Again, no one is going to like it. But I suspect the dinosaurs were not liking things around 65 million years ago either.

No Real Solution to the Problem (As Defined By We Humans)

The human defined problem does not admit to a population crash as a solution. The human defined problem looks to have our cake and eat it too. The human defined problem simply ignores the evidence in favor of things like satisfying the constraints of energy flow by some miraculous technology that will bypass the Second Law of Thermodynamics. The requirement that no one suffer while the population decrease takes place cannot be mapped onto a volume that simultaneously satisfies our many other requirements and does not violate any of the real physical constraints.

If nothing is done to radically alter our current course (business as usual with respect to reproduction and consumption of natural resources) there will be a major population crash. This crash will be felt by every single person on the planet. Admittedly some less developed populations may feel the intensity or immediacy much less than populations in the developed world, but there is no way they will escape the ultimate impacts.

People often imagine that more primitive tribes (such as the one recently “discovered” in the Amazon) will escape the wrath of a population crash and go on surviving as they have for millennia. This ignores the simple fact that many of the fruits of civilization actually do find their ways into many of these sub-populations. In many cases food imports are necessary to keep the population even in steady state.

Furthermore, climate change may have more extreme effects in some of the areas where less developed populations currently live. Nor should we think that some populations will simply migrate from unlivable areas to more livable ones as a result of climate destabilization as, for example, was the case in the several mass movements out of Africa as primitive Homo sapiens expanded into Europe, Asia, and Polynesia.

Even though the major pulses of those movements appear to have been motivated by climate change (ice age glaciations and drying in central Africa), that climate change had greater directionality (less chaotic with a definitive trajectory) and took place over many centuries. The current climate shifts are looking more and more the case of potentially rapid and unpredictable shifts, on the order of decades, that will lead to a much more chaotic weather, greater extremes and locally unusual storms (e.g. the snow and cold in southern states several weeks ago).

Nature, if it were sentient (I personally can't say it isn't!), would define the problem quite differently from what humans have. Nature's problem definition might go like this:

This cancerous species (humans) is creating a global environment in which many species will be driven to extinction. But that is also the environment that they will have to occupy. And the selective forces generated by that environment are not conducive to the sustainability of that species. So the solution is either that the species radically evolve to become benign or the significant disruption of the body (the Ecos) will kill the species, and with it the genus, since there is only one species within that genus extant.

Our requirements are that we don't want to sacrifice anything. We want the process to be painless. The constraints are those imposed by nature, but we also want to bypass those (or some of them) by inventing something that ensures that our two requirements, in all their various forms, will be met. No inconveniences for us. “Surely there is some technology that will help us solve the problem as we have defined it. Surely there is some way to make more usable energy from sunlight — there just has to be.”

Currently we go along as if that technology must be right on the horizon. We don't think about the counterfactual situation (we're actually not wired to do so). What if no great magical technology comes along in time? Then what do we do?

For example, the official policy of the US government is that we ‘pursue’ investment in technology and entrepreneurs to commercialize it. President Obama still insists that there is something called ‘clean coal’, by which he means coal-fired electrical generation that produces much less CO2 gas than ordinary plants. He never took a physics course, I suppose, since he doesn't seem to get that the energy cost of capturing and sequestering CO2 will reduce the net energy production to less than two thirds of an ordinary plant. And that doesn't even address the issue of storing the CO2 (available volume, safety, etc.)

While the president is spouting this delusion everyone else is feeling like we don't have to worry about anything. We don't have to really do anything because the brilliant boys in the backroom will invent the right stuff.

Meanwhile nothing is done. The political solution to the overpopulation problem is to simply ignore it (or deny it if someone dares to bring it up). Don't worry. Be happy (and go out and consume so we can boost the economy). Unfortunately, Nature has a different solution.

What the Numbers Say

As I have written often in these blogs, energy is the key to everything (see: “Economic dynamics and the real danger”). That is, it takes energy flow to build and maintain all physical artifacts and biomass. It takes mechanical and chemical work to make matter into the forms we want it. So without energy flow the entropy version of the Second Law of Thermodynamics takes over and everything turns to dust.

This is the crux of the problem. Our consumption of fossil fuels has permitted us to construct an incredible physical world that has effectively (but only seemingly and only temporarily) insulated us from the vagaries of nature. It has allowed us to produce copious amounts of food and thus allowing us to produce copious amounts of biomass.

Our population numbers today are a direct result of the abundance of energy flow from fossil fuels. And unhappily, we are now at the stage where the extraction rates of those fuels are beginning to decline. We have already passed the peak of production of conventional oil on a global basis. Given the role of oil in the extraction work of the other fuels as well as transportation of goods over long distances, we may effectively be on the verge of the peak of production of all fossil fuel energies.

More importantly, the net energy available, which is the net of the gross amount of energy extracted less the energy required in its extraction, is already in decline. I have written extensively about this so I will not repeat the arguments here. But it is becoming increasingly clear that our global economy is feeling the effects of declining net energy as the captains of industry (including the Chinese) scramble to find new solutions to more costly energy. Lately the price of food has been going up steadily as a result of the increased cost of energy. This is an inescapable law of physics — one unknown and unimagined by the economists and politicians in the world.

Below is a graph from one of my models of the biophysical economy, that is the economy of energy flow through the human built world and the supported biomass (sharp readers will note the similarities between this model and The Limits to Growth model of resource depletion — the difference is that I have focused on energy as the primary resource). These are all aggregated under the concept of assets. People are as much considered assets as buildings and cars and roads.

All assets can be measured in terms of their embodied energy, or how much energy was consumed in creating and maintaining the assets over their life time. When assets decay (or people die) their physical embodied energy is removed from the books, so to speak. Under historical conditions of growth in net energy flow, total assets have been growing. This reflects the increase in population (and to some degree girth) and consumption of goods and services per individual. The graph shows that as net energy grew throughout the industrial, green, and information revolutions the total assets of the biophysical economy grew as well.

Figure 4. Population/economic dynamics are defined by the amount of net energy available to do real work (construction and maintenance of the built world and biomass, e.g. human beings). This graph includes the effects of a sustainable alternative energy revolution due to a crash program (e.g. WWII mobilization) to build alternative energy infrastructure. This was included to show that even with this effort a crash is unavoidable. Total Gross refers to the total amount of raw energy captured, either fossil fuels extracted or sunlight captured (pre-conversion). Net FF is the net fossil fuels after conversion to usable fuels like gasoline. Net Alt. is the net energy derived from alternative sources like solar or wind. Total Net is the sum of net from fossil fuels and alternative sources. Total Assets are all assets produced from net energy measured in embodied energy units (also called emergy).

The red trace shows the growth and decline of net energy from fossil fuels. The green trace at the bottom shows, first, the level of energy from real-time solar inputs, such as food production. It is augmented by a sudden increase in alternative energy after a massive marshalling of resources to build out an alternative energy infrastructure. This infrastructure must be capable of self-sustaining production, i.e. it must replace itself over time without inputs from fossil fuels. The dark blue trace at the top is the total gross energy extracted either in fossil fuels or in alternative forms equivalent to the energy from fossil fuels, e.g. electricity. The purple trace, total net energy, is what society has to work with to produce and maintain assets. You can see by this the effects of adding alternative energies to the net from fossil fuels.

Finally, the light blue line traces total assets being produced by the availability of net energy. This aggregation covers long-term assets like buildings and roads, intermediate-term assets like heavy equipment and automobiles, and short-term assets and consumables. It also represents non-farm biomass assets, namely people, pets, and ornamental plants. What this does not include is unconverted, or natural resources, such as timber, that require work to be done in order to extract a usable product, such as lumber. Everything is measured in energy units required to construct and maintain the assets. For people, of course, this includes all energies expended to grow and keep kids healthy and the energy of food needed to keep people alive. It doesn't take an Einstein to know what happens if you take away the food.

As you can see the dynamics are not favorable. As fossil fuels diminish, after the peak in the red trace, everything starts to diminish, and rapidly. The time scale in the graph from the peak of fossil fuels is roughly one hundred years. That really isn't a long time, even in terms of human history.

The inclusion of alternative energies here is for two purposes. One is to show the scale and rate problems associated with bringing alternatives on-line. So little energy is gotten from these sources now that a scale up even half of what is implied in the graph seems totally unrealistic (in spite of what you might have heard in the main stream media).

The resources that would have to be diverted to accomplish this marshalling would be considerable, requiring sacrifices from everyone in terms of their material lifestyles. Some of my results suggest that the average American citizen will have to give up two-thirds of current income (like a flat tax rate) to support the scale of this kind of effort.

But even if we all agreed to do it, to make the necessary sacrifices, it doesn't really change much. The population will still crash, our assets will still crumble down to the point at which we learn to live only on alternative sources (and remember this requires that they be self-sustaining into the indefinite future). The situation shown in the graph is overly optimistic in my view. It assumes not only a very rapid rise in technologies like solar and wind (roughly 25% growth per year for 40 years followed by 10% per year for another 150 years) but that we could sustain that increase over several centuries. And that just gets us to an economy that is roughly one quarter of what we have today. That does not provide wealth production for would-be developing countries I'm afraid. Everyone living in that economy will be very much poorer in terms of material wealth than the average Eastern European is today.

I've included the outline of some results of other models that do not include such a massive build up of alternative energies. The black line shows the complete plummet of assets when all fossil fuels run out. For those clinging to the belief that we would still have hydroelectric dams and nuclear power plants, think again. Those facilities are also highly dependent on fossil fuels for maintenance. Shut off the fuels and we would see the end of all technological energy within fifty years. At which time the only sources of energy will be the ancient ones, real-time solar and woody biomass.

I suspect the negative impacts of such catastrophic collapse will have serious repercussions on the human psychology that will propel what survivors might remain to acts of unspeakable horror in a vain attempt to survive just a little longer. That is why the black line craters without leveling off. My concern for the latter is that once a collapse starts in earnest there will be a runaway effect that will build such momentum that no human being will be able to survive. Think Cormac McCarthy's novel, The Road, only much worse. McCarthy still allowed a glimmer of hope at the end (same with David Brin's The Postman).

In most of these post apocalyptic stories, there is always the assumption that someone survives and the human species goes on into the future. That may be due to our human-exceptionalism bias, or we just can't imagine a world without us (an exception is Alan Weisman's non-fiction book The World Without Us).

But population crashes have usually been unkind to most other species throughout the history of Earth. From a purely biological perspective there isn't any reason to believe that there isn't some kind of crash situation that wouldn't take us out. Most of the readers will, I'm sure, cling to the belief that someone will survive, surely. But ask yourself on what basis do you believe that? Do you have a carefully thought out rational justification, or are you simply rationalizing? Use critical thinking on your own thinking.

The solid blue line, on the other hand, depicts what could happen if the crash of population is managed and the survivors are the wisest of our kind. Natural energy flows can and will sustain a small population indefinitely. The key is to prepare for that future as best we can. I have indicated that ark colonies based on permaculture practices stand the best chance of survival and do not necessarily have to be based on subsistence living (see “What is a feasible living situation for future humans?” for example).

A Feasible Solution (Just Not the One We Would Have Wanted)

If we redefine the problem, for the benefit of the human genus, not ignoring Nature's definition but trying to find a compromise, might we find a feasible solution volume?

I think the answer is yes. Put very succinctly, if we define the problem as:

We want to reduce the current population of humanity down to the carrying capacity that is reality, at a rate that will put us on track to achieve that goal before we do any more harm to the environment, with minimal pain and suffering, accepting great sacrifices as needed, for the purpose of ensuring that humans will not go extinct.

Then, I believe there is a way to solve this problem. Long-time readers will have already recognized the arc of my arguments from my previous blogs.

I believe there is a solution to this problem. And I believe it involves human choices and intervention in the evolutionary process that brought us into existence.

This section is not what I originally wrote re: what is a feasible solution. My readers will guess what might have been in this section. I sent an early draft to a number of people in the no- or negative-growth community, people who fully get that we have a serious problem. But a large number of those people were extremely uncomfortable with my feasible solution! Most granted that my arguments are basically sound regarding the fate of the human species if a solution cannot be found. But few were willing to accept the conclusions.

My solution, to the modified problem statement, includes a maximally coercive action that is politically unacceptable (or at least politically incorrect!). The need, remember, is to find a way to reduce the population at a rate that will exceed the rate of decline of the carrying capacity. Most people in the ‘population reduction’ movement are queasy over what that will take (look carefully at the graph above and derive your own inferences).

I think I know what will work. It doesn't involve overtly killing anyone. It does seek to minimize pain and suffering. But it baldly admits to a stark reality. I may be alone in a willingness to face that reality. I'm not clear as to why that is the case. But I have no wish to offend the masses. That won't help anyone. So let me just say that the feasible solution is only for the least faint of heart. Of course, if I'm the only one to accept this reality, it won't matter. The worst will come to pass.

Leaving on a Hopeful Note

I am told by several friends who have known my work that I have to leave people with some hope. I'll leave you with two kinds of hope!

First you may seek solace in the knowledge that my claims are based on computer models, which, like statistics, can be rigged to tell you anything you want them to. Or even if you don't accuse me of rigging the model to get the results I want, you could at least believe that computer models are fallible. The programmer is fallible. This is certainly true. So let us hope that I am mistaken and the models are the result of unintentional biases. Because I am only human, they do not depict a realistic scenario nor do they do a good job of predicting the future trends.

Believe it or not I am right there with you on this one. I hope I am way off. Nothing would please me more than discovering a flaw in my models and/or other models demonstrate (flawlessly) that the world will merely enter some kind of steady state condition leaving us all happy and prosperous (and all having ‘green’ jobs).

But the other kind of hope, the one that dominates my thinking now, is that humanity will exercise some sensibility, some good judgment, and recognize the need to bow out gracefully. The actions taken thereafter might just increase the odds for a humanity in the future. Not unlike the man who seeks redemption while dying, perhaps humanity will exercise wisdom as a last act. There is a way to make this work.